/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package javax.el;

import java.util.Iterator;

/**
 * @author Jacob Hookom [jacob/hookom.net]
 */
public abstract class ELResolver {

	public static final String RESOLVABLE_AT_DESIGN_TIME = "resolvableAtDesignTime";

	public static final String TYPE = "type";

	public abstract Object getValue(ELContext context, Object base, Object property) throws NullPointerException, PropertyNotFoundException, ELException;

	/**
	 * @param context  The EL context for this evaluation
	 * @param base     The base object on which the property is to be found
	 * @param property The property whose type is to be returned
	 * @return the type of the provided property
	 * @throws NullPointerException      If the supplied context is <code>null</code>
	 * @throws PropertyNotFoundException If the base/property combination provided to the resolver is
	 *                                   one that the resolver can handle but no match was found or a
	 *                                   match was found but was not readable
	 * @throws ELException               Wraps any exception throw whilst resolving the property
	 */
	public abstract Class<?> getType(ELContext context, Object base, Object property) throws NullPointerException, PropertyNotFoundException, ELException;

	/**
	 * @param context  The EL context for this evaluation
	 * @param base     The base object on which the property is to be found
	 * @param property The property whose value is to be set
	 * @param value    The value to set the property to
	 * @throws NullPointerException         If the supplied context is <code>null</code>
	 * @throws PropertyNotFoundException    If the base/property combination provided to the resolver is
	 *                                      one that the resolver can handle but no match was found
	 * @throws PropertyNotWritableException If the base/property combination provided to the resolver is
	 *                                      one that the resolver can handle but the property was not
	 *                                      writable
	 * @throws ELException                  Wraps any exception throw whilst resolving the property
	 */
	public abstract void setValue(ELContext context, Object base, Object property, Object value) throws NullPointerException, PropertyNotFoundException, PropertyNotWritableException, ELException;

	/**
	 * @param context  The EL context for this evaluation
	 * @param base     The base object on which the property is to be found
	 * @param property The property to be checked for read only status
	 * @return <code>true</code> if the identified property is read only,
	 * otherwise <code>false</code>
	 * @throws NullPointerException      If the supplied context is <code>null</code>
	 * @throws PropertyNotFoundException If the base/property combination provided to the resolver is
	 *                                   one that the resolver can handle but no match was found
	 * @throws ELException               Wraps any exception throw whilst resolving the property
	 */
	public abstract boolean isReadOnly(ELContext context, Object base, Object property) throws NullPointerException, PropertyNotFoundException, ELException;

	public abstract Iterator<java.beans.FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base);

	public abstract Class<?> getCommonPropertyType(ELContext context, Object base);

	/**
	 * Invokes a method on the the given object. This default implementation
	 * always returns <code>null</code>.
	 *
	 * @param context    The EL context for this evaluation
	 * @param base       The base object on which the method is to be found
	 * @param method     The method to invoke
	 * @param paramTypes The types of the parameters of the method to invoke
	 * @param params     The parameters with which to invoke the method
	 * @return Always <code>null</code>
	 * @since EL 2.2
	 */
	public Object invoke(ELContext context, Object base, Object method,
	                     Class<?>[] paramTypes, Object[] params) {
		return null;
	}

}
